Thirty to forty years ago, there was a “great debate” pitting biology versus society in relation to the role of gender. Just as there had been in relation to IQ and school success, and in earlier generations about class and race. Which was more important: nature or nurture?

The reason this debate flared up in the 1970s was the advent of the Women’s Liberation Movement, which confronted gender inequalities and the oppression of women. Women’s Liberation challenged stereotypes about women, inequalities of income and domestic labour, men’s predominance in positions of power and, in due course, men’s violence towards women in the form of rape, domestic abuse, and femicide. All these were seen as social patterns that could and should be revolutionised.

This soon brought the movement up against the cultural justifications of gender inequality. Some justifications were religious, some were folkloric, but some were expressed in more modern language. The most powerful, in the English-speaking world, were the arguments that came to be called “biological essentialism”.

According to this ideology, the social arrangements that feminism challenged expressed differences in character (emotion, intellect, attitude, etc.) between women and men, which were rooted in biological sex differences. These in turn were explained by survival imperatives that had shaped the early stages of human, or hominid, evolution. Thus it followed that men, who did the hunting and fighting, had to be aggressive, dominant, promiscuous, rational, etc. While women, who had the babies and tended the home fires, had to be nurturant, passive, monogamous, emotional, etc.

Biological essentialism itself has evolved. It started by emphasising sex differences in size and muscular strength as the explanation for male dominance. In the era of “sociobiology” such matters as endocrine differences were emphasised, and men were supposed to have a hormonal “aggression advantage”. As the field of “evolutionary psychology” developed, differences of reproductive strategy were emphasised; some of the more toxic literature of this type provided pseudo-biological justifications of rape. In the 1990s, seemingly all attention became fixed on the brain and we began hearing a lot about dichotomous “brain sex”. This notion infested schools for a while, with bizarre ideas about boys’ fixed brain-based “learning styles”. (I have always thought this idea was an insult to boys, who actually have many ways of learning.)

Curiously, whatever biological mechanism was appealed to, the argument always ended up in the same place: Conventional sex roles, gender divisions of labour, and inequalities of power, were biologically determined and therefore could not be challenged. Feminist activism was coming up against nature and so, ultimately, it was futile.

The idea that gender relations are biologically fixed, is shown up as nonsense in the light of the ethnographic and historical evidence of cultural diversity and change. But we can’t substitute a simple “sex role” model instead, assuming that attitudes and emotions are determined by dichotomous roles. One of the most important empirical findings of gender research is that in contemporary affluent societies (at least), there are very few substantial differences in psychological characteristics (attitudes, emotions, intellect, etc.) between men and women. This conclusion flies in the face of popular stereotypes, but is supported by a large body of quantitative evidence.

Biological essentialism gets its influence from the enormous cultural prestige of biological science since Darwin; from its match with the familiar stereotypes of masculinity and femininity in European-derived popular culture, and from its value in shoring up existing structures of power and privilege. It does not get its influence from being good science. Most of it is not science at all. It is, rather, a conservative social rhetoric that cherry-picks those fragments of biological and social research that fit into a pre-determined set of conclusions. It is ideology that uses the rhetoric of science, much as ideology a few hundred years ago used the rhetoric of religion to justify the marginalisation of women. (I can think of a few archbishops, popes and muftis who still do.)

Building a genuine scientific understanding of gender and gender relations is an immense task, involving both biological and social science as well as a rethinking of human history and human evolution. The Women’s Liberation Movement is rightly seen as the modern starting point of gender studies, opening up this whole terrain to serious analysis. Some of its formulations, we can now see, were too simple, but the movement was right in its perception that gender arrangements can and do change historically.

This doesn’t mean that bodies are irrelevant, far from it! Feminism around the world is deeply concerned with perinatal mortality, infant survival, motherhood, HIV/AIDS, unequal nutrition, domestic violence, rape, occupational health, sexual desire, contraception, abortion, and the increasing impact of biotechnology. All of these are issues about embodiment, for which sophisticated biological knowledge is necessary. What we can see now, more clearly than a few decades ago, is that on all these fronts, human bodies are caught up in a historical process, and to understand that, sophisticated social science is also necessary. The knowledge base for activism thus continues to change and develop, but the social justice imperative for activism remains unchanged.